The present invention relates to a framework comprising separably connected profile bars. The connection is achieved by a coupling member consisting of a bearing housing and a holding member incorporated therein in a longitudinally movable manner. The coupling member is inserted into a hollow section of a first profile bar so that stationary coupling projections at an end of the bearing housing protrude from a face end of the bar. A free end of the holding member is provided with a coupling hook which is arranged between the two coupling projections of the bearing housing and also protrudes from the face end of the first profile bar. The pair of coupling projections and the coupling hook thus provide a coupling arrangement which can be inserted in an undercut longitudinal slot of another profile bar, e.g., a vertical column, and locked in position therein.
This locking in position is accomplished through an eccentric pin which extends transversely to the first profile bar, is rotatably supported in the bearing housing and passes through the holding member. An actuating end of the eccentric pin fits a cross hole of the profile bar which accepts the coupling member. During rotation of the eccentric pin, the eccentric of the eccentric pin moves the holding member in the longitudinal direction of the profile bar so that the coupling hook is also moved in the same direction. The coupling hook simultaneously performs a movement transverse to the profile bar, which movement is accomplished due to the fact that the bearing housing is provided with an inwardly and upwardly extending wedge surface and that the holding member has a matching inclined surface which is pressed against the wedge surface by a spring force.
The coupling member of the framework according to the present invention, firstly, is of special design since the coupling arrangements in their initial condition ready for coupling are situated in a common plane, i.e., the movable coupling hook lies between the two coupling projections. Therefore, the longitudinal slot of the profile bar, into which the coupling arrangements are to be engaged, need not be of a greater width than that required for accepting only one coupling arrangement, for example, the stationary coupling projections. In addition to the small opening width of the slot, a closed installation space of the coupling arrangements is achieved. Also, the two stationary coupling projections ensure a clearly defined location of the profile bar equipped with the coupling member during and after the coupling operation.
The design of the coupling member according to the present invention has the additional special feature that the coupling hook not only performs a transverse motion toward the coupling projections but simultaneously, because of the employed control arrangement, a longitudinal motion. Because of these simultaneously affected two motion components, a particularly safe and strong connection is obtained between the two profile bars. The transversely directed motion component first causes a locking in position of the two coupling arrangements at the opposing inner surfaces of the slot opening. This locking in occurs because the coupling hook moving in a transverse direction approaches one inner surface, while the two coupling projections will eventually rest against the opposite inner surface. During this transverse motion, the coupling hook leaves the common plane extending between the coupling projections and moves behind the adjacent wall of the longitudinal slot. Because of the simultaneously effected motion component directed longitudinally, the coupling hook moves against the inner surface of the longitudinal slot wall, bearing against the wall and thereby firmly pressing one profile bar against the face of the other profile bar which carries the coupling member. In this manner, one profile bar is pushed against the other.
In the case of known frames using coupling members in accordance with German utility model No. 73 71 203.0, the coupling member consists of numerous detail parts thereby making the manufacture per unit more expensive and requiring a laborious and time-consuming assembly of the coupling member at the profile bar. The holding member consists of a plate which, with its sloping shoulders, is forced against wedges of the bearing housing by a spring resting against an eccentric pin. Special locating devices, such as a circlip and an annular shoulder at the pin shaft, are required to secure the eccentric pin in the bearing housing. This locating in position makes the assembly of the components within the hollow section of the profile bar accepting the coupling member extremely difficult. Locating the pin relative to the bearing housing, however, is essential because the spring has the tendency to force the pin out of a cross hole in the profile bar. Moreover, it is nearly impossible to remove an installed coupling member in order to replace, for example, a broken spring without damaging the member.
The present invention has as an object to develop a framework for rapid and easy assembly of the initially mentioned type, whose coupling member consists of the most simple and easy-to-assemble and disassemble components for convenient installation in the profile bar and removal from the same as required.
This object and others are achieved by the present invention with a coupling member consisting of only three components, i.e., a bearing housing, a holding member specially formed from a sheet metal strip, and an eccentric pin. A resilient tongue cut out of the sheet metal strip of the holding member performs two different spring functions. One function is to keep the matching inclined surface of the holding member in contact with a wedge surface of the bearing housing. The other spring function is to load the eccentric pin like a pushbutton so that, by exerting an axial pressure, the pin can be pressed into the bearing housing until it comes out of the cross hole in the profile bar. This arrangement enables convenient installation and removal of the coupling member into and out of the profile bar.
According to the present invention the coupling member is an assembly which can be prefabricated from the above-mentioned three components for insertion into any profile bar provided with a cross hole. For insertion, all that has to be done is to press in the eccentric pin at its actuating end in an axial direction as described above. As soon as the coupling member has reached its specified location in the hollow section of the profile bar, the actuating end will automatically engage into the cross hole of the profile bar. This engagement accurately determines the location of the coupling member in the profile bar, especially if the mentioned stationary coupling projections at the bearing housing are provided with locating shoulders which will be arranged in front of the face of the profile bar. No additional locking elements are required to secure the coupling member in the profile bar.
According to another special aspect of the present invention, the controlling eccentric disk of the pin is located at the side of the holding member opposite the resilient tongue and acts as a stop which, with its outer face, bears against the inner side wall of the bearing housing. This defines the initial position of the "pushbutton" formed by the eccentric pin in the unpressed condition. The actuating end of the eccentric pin protrudes correspondingly from the bearing housing and enters the cross hole of the profile bar to the desired extent. When pressing in this "pushbutton", the control end of the holding member is caught by the eccentric disk thus deforming the resilient tongue.
The small number of components for the coupling member, and its securing in position in the profile bar, are possible because the holding member in accordance with the present invention simultaneously performs several functions. Firstly, of course, the front end coupling hook and the rear end control required for acting on the eccentric pin are formed from a sheet metal strip. The control may be one-sided projections, e.g., bent edge strips forming rails on one surface of the holding member against which the eccentric disk is arranged to effect the desired inward or outward thrust of the holding member during the rotational actuation of the eccentric pin. The second function of the holding member in accordance with the invention consists of the previously mentioned double spring function of the cut out resilient tongue, which is utilized for both maintaining contact between the holding member, the bearing housing and the pushbutton effect of the eccentric pin. A third function of the holding member is securing the eccentric pin in its installed end position in the bearing housing.
This last mentioned function is achieved in the following manner. In order to enable convenient assembly, when the holding member in accordance with the invention together with the eccentric pin is inserted into the bearing housing, a rear portion of the bearing housing is provided with a wall cut-out. Without the solution in accordance with the present invention, there is a risk that the eccentric pin may fall out of the wall cut-out unless additional locating means are provided. The invention overcomes this problem simply with a control arrangement which keeps the eccentric pin in a surrounding grip and, similar to an anchor, engages behind the wedge surface with the matching inclined surface produced by bending the sheet metal strip. This engagement is reliably secured through the above-mentioned spring action of the resilient tongue formed in the sheet metal strip. In this way, the resilient tongue performs a third function, i.e., the location of the eccentric pin in its installed position in the wall cut-out.
The space between the two coupling projections of the bearing housing is preferably utilized for the wedge surface, which provides, in particular, the following advantages. Firstly, the wedge surface is brought very far to the front and commences before the face of the profile bar so that in a coupling situation, the wedge surface also engages the slot opening. The connection between the two coupling projections causes a reinforcement of the mutual position of the two coupling projections. The portion of the holding member at this far advanced wedge surface is very short and therefore relatively stiff although a resilient sheet metal strip is used for forming the holding member. Finally, the advanced wedge surface enables an accumulation of material in this area of the bearing housing, which material produces a side wall against the outside, because reference surfaces are preferably provided at the inside of the side walls, which serve as guides for the holding member during assembly and disassembly. In the present case the reference surface can be integral with the material accumulation. Another reference surface of this kind can be provided in the bearing area of the eccentric pin.
In order to positively prevent the "pushbutton function" of the eccentric pin from occurring in the coupling position, it is preferable to provide stops in the bearing housing, which protrude as locking features into the path of the movable parts only in the coupling position. The stops, i.e., in the removal position, are arranged outside of this path.
To ensure satisfactory distribution of the spring functions provided by the resilient tongue, it is preferred to arrange the tongue in the central section of the sheet metal strip so that the spring force is acting equally on the front coupling hook and the rear control arrangement of the holding member so as to develop the mentioned spring functions.
For securing the holding member, it is preferred that the coupling hook contacts the inner surface of the slot wall engaged behind in two points only. This contact can be achieved by simply arranging the edge of the coupling hook to be of curved shape.
Further advantages and measures of the invention will become evident from the claims, the drawings and the following description which explains in detail a preferred embodiment of the present invention.